Greeting, FYI, we noticed the following commit (built with gcc-9): commit: 8d892a300af5d531ed5af5684706bab1146db33b ("[RFC RFT PATCH v2 2/2] mtd: core: introduce of support for dynamic partitions") url: https://github.com/0day-ci/linux/commits/Ansuel-Smith/Add-nvmem-support-f... base: https://git.kernel.org/cgit/linux/kernel/git/mtd/linux.git mtd/next patch link: https://lore.kernel.org/linux-mtd/20220220173905.14165-3-ansuelsmth@gmail... in testcase: boot on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): If you fix the issue, kindly add following tag Reported-by: kernel test robot <oliver.sang(a)intel.com&gt; [ 2.362523][ T1] BUG: kernel NULL pointer dereference, address: 000003a8 [ 2.362925][ T1] #PF: supervisor read access in kernel mode [ 2.362925][ T1] #PF: error_code(0x0000) - not-present page [ 2.362925][ T1] *pde = 00000000 [ 2.362925][ T1] Oops: 0000 [#1] [ 2.362925][ T1] CPU: 0 PID: 1 Comm: swapper Not tainted 5.17.0-rc1-00042-g8d892a300af5 #1 [ 2.362925][ T1] EIP: mtd_check_of_node (include/linux/device.h:794 drivers/mtd/mtdcore.c:595) [ 2.362925][ T1] Code: c6 53 83 ec 08 3d 08 ff ff ff 74 0d 83 b8 a8 03 00 00 00 0f 85 a0 00 00 00 8b 86 24 04 00 00 3d 08 ff ff ff 0f 84 8f 00 00 00 <8b> b8 a8 03 00 00 85 ff 0f 84 81 00 00 00 ba 2b cc 38 42 89 f8 e8 All code ======== 0: c6 (bad) 1: 53 push %rbx 2: 83 ec 08 sub $0x8,%esp 5: 3d 08 ff ff ff cmp $0xffffff08,%eax a: 74 0d je 0x19 c: 83 b8 a8 03 00 00 00 cmpl $0x0,0x3a8(%rax) 13: 0f 85 a0 00 00 00 jne 0xb9 19: 8b 86 24 04 00 00 mov 0x424(%rsi),%eax 1f: 3d 08 ff ff ff cmp $0xffffff08,%eax 24: 0f 84 8f 00 00 00 je 0xb9 2a:* 8b b8 a8 03 00 00 mov 0x3a8(%rax),%edi <-- trapping instruction 30: 85 ff test %edi,%edi 32: 0f 84 81 00 00 00 je 0xb9 38: ba 2b cc 38 42 mov $0x4238cc2b,%edx 3d: 89 f8 mov %edi,%eax 3f: e8 .byte 0xe8 Code starting with the faulting instruction =========================================== 0: 8b b8 a8 03 00 00 mov 0x3a8(%rax),%edi 6: 85 ff test %edi,%edi 8: 0f 84 81 00 00 00 je 0x8f e: ba 2b cc 38 42 mov $0x4238cc2b,%edx 13: 89 f8 mov %edi,%eax 15: e8 .byte 0xe8 [ 2.362925][ T1] EAX: 00000000 EBX: 44e20800 ECX: 00000000 EDX: 00000000 [ 2.362925][ T1] ESI: 44e20800 EDI: 00000001 EBP: 403a5e44 ESP: 403a5e30 [ 2.362925][ T1] DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 EFLAGS: 00010213 [ 2.362925][ T1] CR0: 80050033 CR2: 000003a8 CR3: 02d0c000 CR4: 000406d0 [ 2.362925][ T1] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 2.362925][ T1] DR6: fffe0ff0 DR7: 00000400 [ 2.362925][ T1] Call Trace: [ 2.362925][ T1] ? add_mtd_device (include/linux/device.h:793 include/linux/mtd/mtd.h:469 drivers/mtd/mtdcore.c:731) [ 2.362925][ T1] ? lockdep_init_map_type (kernel/locking/lockdep.c:4810) [ 2.362925][ T1] ? debug_mutex_init (kernel/locking/mutex-debug.c:89) [ 2.362925][ T1] ? __mutex_init (kernel/locking/mutex.c:53) [ 2.362925][ T1] ? mtd_device_parse_register (drivers/mtd/mtdcore.c:1027) [ 2.362925][ T1] ? mtdram_init_device (drivers/mtd/devices/mtdram.c:146) [ 2.362925][ T1] ? init_mtdram (drivers/mtd/devices/mtdram.c:171) [ 2.362925][ T1] ? init_pmc551 (drivers/mtd/devices/mtdram.c:153) [ 2.362925][ T1] ? do_one_initcall (init/main.c:1300) [ 2.362925][ T1] ? parse_args (kernel/params.c:131 kernel/params.c:188) [ 2.362925][ T1] ? do_basic_setup (init/main.c:1372 init/main.c:1389 init/main.c:1408) [ 2.362925][ T1] ? kernel_init_freeable (init/main.c:1615) [ 2.362925][ T1] ? rest_init (init/main.c:1494) [ 2.362925][ T1] ? kernel_init (init/main.c:1504) [ 2.362925][ T1] ? ret_from_fork (arch/x86/entry/entry_32.S:772) [ 2.362925][ T1] Modules linked in: [ 2.362925][ T1] CR2: 00000000000003a8 [ 2.362925][ T1] ---[ end trace 0000000000000000 ]--- [ 2.362925][ T1] EIP: mtd_check_of_node (include/linux/device.h:794 drivers/mtd/mtdcore.c:595) [ 2.362925][ T1] Code: c6 53 83 ec 08 3d 08 ff ff ff 74 0d 83 b8 a8 03 00 00 00 0f 85 a0 00 00 00 8b 86 24 04 00 00 3d 08 ff ff ff 0f 84 8f 00 00 00 <8b> b8 a8 03 00 00 85 ff 0f 84 81 00 00 00 ba 2b cc 38 42 89 f8 e8 All code ======== 0: c6 (bad) 1: 53 push %rbx 2: 83 ec 08 sub $0x8,%esp 5: 3d 08 ff ff ff cmp $0xffffff08,%eax a: 74 0d je 0x19 c: 83 b8 a8 03 00 00 00 cmpl $0x0,0x3a8(%rax) 13: 0f 85 a0 00 00 00 jne 0xb9 19: 8b 86 24 04 00 00 mov 0x424(%rsi),%eax 1f: 3d 08 ff ff ff cmp $0xffffff08,%eax 24: 0f 84 8f 00 00 00 je 0xb9 2a:* 8b b8 a8 03 00 00 mov 0x3a8(%rax),%edi <-- trapping instruction 30: 85 ff test %edi,%edi 32: 0f 84 81 00 00 00 je 0xb9 38: ba 2b cc 38 42 mov $0x4238cc2b,%edx 3d: 89 f8 mov %edi,%eax 3f: e8 .byte 0xe8 Code starting with the faulting instruction =========================================== 0: 8b b8 a8 03 00 00 mov 0x3a8(%rax),%edi 6: 85 ff test %edi,%edi 8: 0f 84 81 00 00 00 je 0x8f e: ba 2b cc 38 42 mov $0x4238cc2b,%edx 13: 89 f8 mov %edi,%eax 15: e8 .byte 0xe8 To reproduce: # build kernel cd linux cp config-5.17.0-rc1-00042-g8d892a300af5 .config make HOSTCC=gcc-9 CC=gcc-9 ARCH=i386 olddefconfig prepare modules_prepare bzImage modules make HOSTCC=gcc-9 CC=gcc-9 ARCH=i386 INSTALL_MOD_PATH=<mod-install-dir> modules_install cd <mod-install-dir> find lib/ | cpio -o -H newc --quiet | gzip > modules.cgz git clone https://github.com/intel/lkp-tests.git cd lkp-tests bin/lkp qemu -k <bzImage> -m modules.cgz job-script # job-script is attached in this email # if come across any failure that blocks the test, # please remove ~/.lkp and /lkp dir to run from a clean state. --- 0DAY/LKP+ Test Infrastructure Open Source Technology Center https://lists.01.org/hyperkitty/list/lkp@lists.01.org Intel Corporation Thanks, Oliver Sang